- Rationale - Acute rhinosinusitis (ARS) is a condition caused by inflammation of the nose and the paranasal sinuses that generally lasts up to 4 weeks. Despite ARS being a self-limiting condition, untreated or inadequately treated sinus infection can lead to the development of complications. Uncomplicated ARS is a subset of ARS and is distinguished from the common cold by the persistence or the worsening of sinus inflammation after the usual period for recovery of viral infection of the nasal cavity (i.e., 10 days). Clinically the difference is based on the following criteria: symptoms are present at least 10 days but less than 4 weeks beyond the onset of upper respiratory symptoms OR symptoms worsen after 5 days from their onset.